Tribological Capabilities of Graphene and Titanium Dioxide Nano Additives in Solid and Liquid Base Lubricants

Abstract

In this study, the tribological behavior of both liquid (oil) and semi-liquid (grease) lubricants enhanced by multilayer graphene nano platelets and titanium dioxide nano powder was evaluated using ball-on-disk and shaft-on-plate tribo-meters. Oil samples for both 2D graphene nano platelets (GNP) and titanium nanopowders (TiNP) were prepared at three concentrations of 0.01 %w/w, 0.05 %w/w and 0.1 %w/w. In addition, 0.05% w/w mixtures of GNP and TiNP were prepared with three different ratios to analyze collective effects of both nano additives on friction and wear properties. For semi-liquid lubricants, 0.5% w/w concentrations were prepared for both nano additives for shaft-on-plate tests. Viscosity and oxidation stability tests were conducted on the liquid-base lubricants. Nano powders of both additive and substrate were analyzed using transmission electron microscopy (TEM) and scanning electron microscopy (SEM). In addition, Raman spectroscopy was conducted to characterize the graphene and titanium dioxide. The study shows that adding graphene and titanium dioxide individually sacrifices either the wear or friction of lubricants. However, use of both additives together can enhance friction resistance and wear preventive properties of a liquid lubricant significantly. For a semi-liquid lubricant, the use of both additives together and individually reduces friction compared to base grease.

The Effecting of Various Parameters on the Thermophysical and Rheological Properties of SiO2 Nano-lubricating Oil in Petroleum Refineries

“…NPs concentrations of 0.25 %, 0.5%, 0.75%, and 1%. These findings are in line with those of several other researchers [22,23,[33][34][35][36]. In general, managing the quality of nano-lubricating oil is a critical component of improving lubricant specifications for increased energy conservation in the mechanical system inside the engine [3,4,22,23].…”

Latest developments in designing advanced lubricants and greases for electric vehicles—An overview

“…As compared to traditional oils, conventional greases contain a variety of properties (i.e., electrical and thermal), which are preferable at especially high temperatures, pressures and extreme conditions 25 . Patel et al evaluated the effect of adding either multi‐layer graphene, TiO 2 nano‐particles, or hybrid nano‐composites containing both nano‐materials to commercially available white grease 41 . The tribological experiments were conducted for different normal loads while keeping the temperature constant at 150C.…”

“…25 Patel et al evaluated the effect of adding either multi-layer graphene, TiO 2 nano-particles, or hybrid nano-composites containing both nano-materials to commercially available white grease. 41 The tribological experiments were conducted for different normal loads while keeping the temperature constant at 150 C. For normal loads of 10 and 20 N, a noticeable friction reduction was achieved for 0.5 wt% TiO 2 and 0.5 wt% graphene + TiO 2 at a concentration ratio of 1:3, respectively. Rawat et al used a four-ball tester to test the performance of paraffin grease combined with three graphene additive variants: graphene oxide (GO), reduced graphene oxide (rGO) and octadecylamine-functionalized graphene oxide (GO-ODA) with varying concentration (0.01-0.05 wt%).…”

Sustainability Evaluation of Machining Ti6Al4V with Graphene Inclusion

“…Friction coefficient decreased by 30-35% compared to dry friction condition and resulted in crack-free surface and reduced debris. Patel et al [17] investigated the tribological behavior of liquid lubricant and semiliquid lubricant by adding graphene platelets and titanium dioxide. In the case of liquid lubricant, the use of 0.05wt% of graphene showed a good reduction in coefficient of friction, while the use of 0.1 wt.% of titanium dioxide showed more wear resistance.…”